A Simplified Fe-Based PhotoATRP Using Only Monomers and Solvent.

A photoinduced atom transfer radical polymerization (photoATRP) of methacrylates is investigated using air-stable FeBr3 as catalyst in the absence of conventional ATRP initiators, additional ligands, reducing agents, and/or radical initiators. The ATRP alkyl halide initiator is formed in situ via photoreduction of FeBr3 by methacrylate monomers. The kinetics of the polymerization display a linear semilogarithmic plot after several hours of induction period. The molecular weight can be modulated by additions of different amounts of FeBr3 , and polymers have narrow molecular weight distributions. Thus, FeBr3 acts as deactivator, as well as a source of activator FeBr2 and initiator. This method features a temporal control, and can provide various polymethacrylates with high chain end functionality.